The dirty dozen

The 12 toxic chemicals banned by the Stockholm Convention on Persistent Organic Pollutants are:

Aldrin

A pesticide used to control termites in tree nurseries and buildings, insects in grain storage, soil pests on cornfields and possible control of tsetse flies. It probably is no longer produced, but stockpiles could still be used. Aldrin is toxic and carcinogenic.

Chlordane

A pesticide used to control termites and ants in buildings, crops, nurseries and forest plantations and to control the Rhinoceros beetle. Last manufacturer stopped production in 1997, but stockpiles could still be used. Chlordane harms the immune system.

Dieldrin

A pesticide with uses similar to those of Aldrin. It also probably is no longer manufactured, but stockpiles could still be used. Dieldrin harms the reproductive system.

DDT

A pesticide used to control malaria-carrying mosquitoes, tsetse flies and illegal control of crop pests. Up to 50,000 tons are estimated to be produced per year. DDT harms the reproductive system.

Endrin

A pesticide used to control pests in corn, rice, cotton and sugarcane crops, and to control mice. It probably is not produced anymore, and it seems not to be used. Endrin is carcinogenic.

Heptachlor

A pesticide used to control termites and ants in buildings, crops, nurseries and forest plantations, and to control cut worms. Last manufacturer stopped production in 1997, but stockpiles might still be used. Heptachlor is carcinogenic and harms the reproductive system.

Mirex

A pesticide used to control termites and ants in crops, grassland, forests and buildings. Also used as a fire retardant. Some production of smaller quantities may still take place. Mirex is carcinogenic.

Toxaphene

A pesticide used in agriculture and mosquito control. Toxaphene can cause thyroid tumours and cancer.

Polychlorinated biphenyls (PCBs)

Industrial chemicals used in electric transformers and capacitors, and as additives in paint, carbonless copy paper and plastics. PCBs are linked to reproductive failure and suppression of the immune system in various wild animals.

Hexachlorobenzene

A pesticide and industrial chemical used as fungicide. It is probably not produced as a fungicide anymore, but it is a byproduct of the manufacturing of other chemicals. Hexachlorobenzene harms the immune and reproductive systems.

Dioxins

An industrial byproduct created by car emissions and the burning of waste. Dioxins are carcinogenic and harm the reproductive and immune systems.

Furans

Toxic byproducts of waste burning and industrial production.

Information supplied by the U.N. Environment Programme.